Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Oct. 28, 2017	Apr. 29, 2017
Assets:
Cash equivalents	$ 3,000	$ 6,798
Deferred purchase price receivable	129,098	119,798
Derivative instruments	967	1,188
Total assets	133,065	127,784
Liabilities:
Derivative instruments	967	1,188
Fair Value, Inputs, Level 1
Assets:
Cash equivalents	3,000	6,798
Deferred purchase price receivable	0	0
Derivative instruments	0	0
Total assets	3,000	6,798
Liabilities:
Derivative instruments	0	0
Fair Value, Inputs, Level 2
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	0	0
Derivative instruments	967	1,188
Total assets	967	1,188
Liabilities:
Derivative instruments	967	1,188
Fair Value, Inputs, Level 3
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	129,098	119,798
Derivative instruments	0	0
Total assets	129,098	119,798
Liabilities:
Derivative instruments	$ 0	$ 0